package cn.bellychang.leetcode.question617;

/**
 * @author ChangLiang
 * @date 2021/3/15
 */
public class Solution2 {

    public TreeNode mergeTrees(TreeNode root1, TreeNode root2) {

        if(root1==null && root2==null){
            return null;
        }
        if(root1==null && root2!=null){
            return root2;
        }
        if (root1 != null && root2 == null) {
            return root1;
        }

        root1.val = root1.val + root2.val;
        root1.left = mergeTrees(root1.left, root2.left);
        root1.right = mergeTrees(root1.right, root2.right);
        return root1;
    }
}
